Related papers: The standard model at low energies
We show that in the presence of massive particles such as nucleons, the standard low energy expansion in powers of meson momenta and light quark masses in general only converges in part of the low energy region. The expansion of the scalar…
In this work we study the low energy kaon-hyperon interaction considering effective chiral Lagrangians that include kaons, $\sigma$ mesons, hyperons and the corresponding resonances. We calculate the scattering amplitudes, and then the…
The large-$N_c$ limit of the meson-baryon effective Lagrangian is shown to reduce to a semiclassical field theory. A chiral bag structure emerges naturally in the $N_c\rightarrow \infty$ limit. A possible connection between the chiral bag…
I discuss a low-energy effective field theory which permits the full treatment of isospin-breaking effects in semileptonic weak interactions. In addition to the pseudoscalars and the photon, also the light leptons have to be included as…
We discuss the low-energy analysis of models involving quarks and four-fermion couplings. The relation with QCD and with other models of mesons and meson plus quarks at low energies is discussed. A short description of how the heat-kernel…
A short overview of the current state of Chiral Perturbation Theory is given. This includes a description of the basic assumptions, the usefulness of the external field method is emphasized using a simple lowest order example. Then at…
We review recent progress in the understanding of low-energy baryon structure by means of chiral perturbation theory. In particular, we discuss the application of this formalism to the description of the quark mass dependence of recent…
I review the use of effective lagrangians in describing the physics beyond the standard model, several theoretical and practical aspects are discussed. It is argued that the only situations where new physics can be observed corresponds to…
In these lectures I make an introduction to chiral unitary theory applied to the meson baryon interaction and show how several well known resonances are dynamically generated, and others are predicted. Two very recent experiments are…
I discuss the recent attempts to build an effective chiral Lagrangian incorporating massive resonance states. A useful approximation scheme to organize the resonance Lagrangian is provided by the large-Nc limit of QCD. Integrating out the…
By means of a coupled channel non-perturbative unitary approach, it is possible to extend the strong constrains of Chiral Perturbation Theory to higher energies. In particular, it is possible to reproduce the lowest lying resonances in…
We study certain physical observables of isoscalar heavy baryons using potential models based on hadronic degrees of freedom. The goal is to compare these results with those from an effective theory obtained in a combined heavy quark and…
A momentum-dependent formulation based on a stationary spin-0 and isospin-1 dibaryon field is proposed to improve convergence of chiral effective field theory in the $\cs{1}{0}$ channel of $NN$ scattering. Although the two-parameter…
In these lectures we discuss the uses of effective field theory in studying dense hadronic matter. We focus on two regimes in the phase diagram. At low baryon density nucleons can be described as non-relativistic point particles interacting…
Starting with the general principles of global and local symmetries, the effective pion-nucleon lagrangian, essentially non-linear in pion field, to describe the non-strange hadrons low-energy electro-weak transitions is developed. We…
We study the S-wave interaction of mesons with baryons in the strangeness S=0 sector in a coupled channel unitary approach. The basic dynamics is drawn from the lowest order meson baryon chiral Lagrangians. Small modifications inspired by…
The construction of effective Lagrangians commonly involves the application of the `classical equation of motion' to eliminate redundant structures and thus generate the minimal number of independent terms. We investigate this procedure in…
In these notes we present an introductory review on various topics about low energy pion physics (some kaon physics is discussed as well). Among these, we include the uses of analyticity and unitarity to describe partial wave amplitudes…
We investigate the existence of bound states of baryons in a kaon condensate using chiral mean field theory. The interactions are described by an effective SU(3)_L X SU(3)_R chiral lagrangian where terms of higher order in density, baryon…
We construct an effective Lagrangian which describes interactions of heavy and light hadrons utilizing the chiral flavor symmetry for light quarks and heavy quark symmetry. For both light and heavy sector we include pseudo scalars, vectors…